* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

body {
    flex-direction: column;
    justify-content: space-between;
    align-items: center;
    min-height: 100vh;
    font-family: arial;
    background: #2980b9;
    background-image: linear-gradient(to top left, #2980b9, #1abc9c);
    position: relative;
    text-align: center;
}

h1 {
    letter-spacing: 0.2em;
    text-align: center;
    padding: 20px 5px;
    color: whitesmoke;
}

/* 提示框 */
#modal {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    position: fixed;
    z-index: 10;
    top: 0;
    height: 1800px;
    width: 100%;
    background: rgba(0, 0, 0, 0.5);
    text-align: center;
}
.modal-box {
    padding: 30px;
    margin: auto;
    width: 240px;
    background: whitesmoke;
    border-radius: 2px;
    text-align: center;
    box-shadow: 0 0 2px 3px rgba(0,0,0,0.3);
}
.modal-box p {
    color: #2980b9;
    font-size: 24px;
    letter-spacing: 0.1em;
}
.play {
    width: 160px;
    margin: auto;
    padding: 10px;
    border: solid 1px #2980b9;
    border-radius: 2px;
    cursor: pointer;
}
.play:hover {
    color: whitesmoke;
    background: #2980b9;
    background-image: linear-gradient(to top left, #2980b9, #1abc9c);
    background-size: 120%;
}

.controllers {
    display: flex;
    width: 320px;
    padding: 5px;
    text-align: center;
    align-items: center;
}

.start, .mode {
    width: 60px;
    margin-right: 5px;
    padding: 4px;
    border: solid 1px #2980b9;
    border-radius: 2px;
    cursor: pointer;
}
.click {
    background: #1abc9c;
    color: white;
}
.emoji {
    margin-left: 5px;
}
.time {
    margin-left: 24px;
    width: 80px;
    text-align: right;
}

/* table style */
section {
    width: 320px;
    height: 380px;
    background: whitesmoke;
    margin: auto;
    text-align: center;
}

/* mine body style */
.mine-body {
    width: 320px;
    height: 320px;
    background: whitesmoke;
    padding: 4px;
}

.cell {
    width: 10%;
    height: 10%;
    cursor: pointer;
    text-align: center;
    border: solid #3498db 1px;
    color: #333;
    font-size: 0;
}

.backgrounded {
    background: #2980b9;
    background-image: linear-gradient(to top left, #2980b9, #1abc9c);
    background-size: 150%;
}

.backgrounded:hover, .start:hover, .mode:hover {
    background: #3498db;
}

.opened {
    font-size: 20px;
    background: whitesmoke;
}

.space {
    font-size: 0;
}

.bomb {
    font-size: 0;
    background: crimson;
    background: url('png/label-03.png');
    background-size: 100%;
}
.flag {
    font-size: 0;
    background: url('png/label-01.png');
    background-size: 100%;
}
.hidden {
    display: none !important;
}

footer {
    text-align: center;
    padding: 5px;
    color: whitesmoke;
    font-size: 14px;
}
footer a {
    color: #333;
    text-decoration: none;
}
footer a:hover {
    color: whitesmoke;
    text-decoration: underline;
}